problem

1.Cannot call out the copy and paste menu bar when the CupertinoTextField is empty. I updated it ##37042, but the problem is still not solved. This situation can only be temporarily resolved when I type in the text and then call out the menu bar once.

2.When the background is white, the horizontal lines in the dialog box are obviously invisible, and they can only be seen when the background is colored.

3.In the case of Chinese, part of the text in the CupertinoTextField menu bar is obviously cropped.

4.In case the CupertinoTextField has only hint and is Chinese, the cursor only shows a part, but input text will be fully displayed.

5.In China, people prefer to use third-party keyboard programs. But unfortunately, in Flutter CupertinoTextField, the following shortcuts don't respond, but it's clear that the native EditText doesn't have this problem. ##27880
these shortcuts are copy, paste, select all, cut, ltrb select, delete text, etc...

I hope that it can be solved as soon as possible, let flutter be perfect